1. Technical Field
The disclosure relates generally to air filtering, and more particularly, to a system for ice and/or frost prevention using guided wave energy, and a turbine including such a system.
2. Background Art
Turbines use a filtered airflow that is pulled into the turbine through an inlet. Typically, a housing positions the filter(s) at the inlet. One challenge for this structure is that ice and/or frost accumulates on the filtrate(s) inside of the housing in sub-freezing conditions. Consequently, the turbine inlet filter needs de-icing and anti-icing processes in cold days. One approach to preventing icing includes re-routing exhaust heat (e.g., steam, gas exhaust or compressor discharge air) to the housing to elevate the inlet air temperature above the freezing temperature. However, this approach requires complex piping and results in performance losses due to the inefficient use of the energy. In another approach, ice melting and prevention is be achieved by introducing thermal energy only to ice and the icing surfaces using high frequency (wavelength 800 nm-300 mm), propagating microwave energy via radiators in the airflow inlet. This approach is ineffective because the propagating nature of the energy results in the energy density being too small to increase temperature, especially for larger filter housings. Enlarging the microwave energy source is expensive.